Perforator control mechanism



Aug. 19, 1952 J. R. ANDERSON PERFORATOR CONTROL MECHANISM 4 Sheets-Sheet 1 Filed April 18, 1947 I INVENTOR.

JJ/wajz'. M77507? Aug. 19, 1952 J. R. ANDERSON PERFORATOR CONTROL MECHANISM 4 Sheets-Sheet 2 i g IllIIIHIIIllllllllifilllllfl' Filed April 18, 1947 66 64 59 Q JNVENTOR.

dokrdflflrzaensm g 19, 1952 J. R. ANDERSON 2,607,421

PERFORATOR CONTROL MECHANISM Filed April 18, i947 4 Sheets-Sheet 5 Aug. 19, 1952 J. R. ANDERSON 2,607,421

PERFORATOR CONTROL MECHANISM Filed April 18, 1947 1 4 Sheets-Sheet 4 IN V EN TOR.

Patented Aug. 19, 1952 2,607,421 PERFORATOR CONTROL MECHANISM John R. Anderson, Chicago, 111., assignor to The American Perforator Company, Chicago, 111., a corporation of Illinois Application April 18, 1947, Serial No. 742,308

14 Claims.

This invention relates to business machines and particularly to electrically controlled and operated perforating machines.

An object of the invention is to provide an improved perforating machine which operates automatically upon insertion therein of a sheet to be perforated whereby to mark the sheet.

A further object is .to provide, in a perforator control mechanism, improved paper registration meansto insure proper positioning of the sheet prior to operation of the perforator. In one embodiment of the invention this object is achieved by arranging, in combination, a pair of seriesconnected paper detecting switches to be engaged by leading edge portions of a sheet, and a clutch-operating circuit which is closed only when these two switches are closed.

In connection with the foregoing, another object is to so arrange the paper switches that proper registration of both the front and side edges of a sheet is assured.

A still further object is to provide a perforating machine having simple, economical and dependable means for effecting a punching operation whereby-to mark a sheet automatically upon insertion of a sheet and thereafter preventing unwanted repetition of the punching operation until the perforated sheet is withdrawn and a new sheet is inserted. To accomplish the foregoing I provide, in conjunction with the paper switches and a clutch-operating circuit as above described, control means including a cut-off switch actuated by a movable portion of the perforator mechanism, a declutching means the operation of which is timed by the cut-off switch (thereby avoiding the necessity of using a relatively expensive time delay relayor like device for this purpose) and holding meansto prevent re-engagement of the'power "clutch so long as the perforated sheet remains in the machine.

The above and other objects, features and advantages of the invention will be apparent from the following specification-when taken in connection with the accompanying drawings wherein certain preferred embodiments are set forth for purposes of illustration, 7 v

In the drawings, wherein like reference numerals refer to like parts throughout:

Fig. l is a perspective view of a perforating machine to which the principles of my invention may be applied; Y 1

Fig. 2 is a perspective View of certain parts of the structure showing the manner in which my invention is embodied therein;

Fig. 3 is a view, partially in longitudinal section, of the machine shown in Fig. 1

Fig. 4 is a plan view of the machine housing removed therefrom;

Fig. 5 is a plan view of the paper detecting switches in relation to a sheet that is being inserted into the machine;

Fig. 6 is a plan view showing the paper detecting switches in relation to a sheet that has been perforated by the machine;

Fig. 7 is a wiring diagram of the machine;

Fig. 8 is a perspective view similar to Fig. 2 but showing a modified form of the invention;

Fig. 9 is a side elevational view of the clutch and associated parts, certain portions being shown broken away; and

Fig. 10 is a plan view of the construction of Fig. 9, certain parts being broken away.

Referring to the drawings and particularly to Figs. l-4 thereof, the machine comprises a base 10, a die shoe 12, a perforator head assembly 14 (hereinafter referred to simply as a perforator head) and a motor 16 for actuating the perfo rato-r head M. A housing l8 encloses the working parts of the machine. The punches 20 are mounted in a punch holder 22 supported by the die shoe l2. The perforator head l4 carries a series of punch-selecting and actuating rings 24 which are mounted in a ring cage 25. These rings 24 are adapted to be set by hand for selective actuation of the punches 20. The sheet or sheets of paper as S, Fig. 2, that are to be perforated and thereby marked are inserted in the gap between the punch holder 22 and a die plate 26 on the die shoe l2. The perforator head [4, when actuated by the motor 16, is depressed and, through the medium of the rings 24, is effective to actuate selected ones of the punches 20 in accordance with the settings of the rings 24 to perforate data or other indicia in the sheet S. I

The construction of the perforator head l4 and the mechanism for coupling this head to the driving motor 16 are disclosed in Rix Patent 2,099,230 dated November 16, 1937. The perforator head [4 includes asupporting frame comprising a plurality of plates or arms 28 extending longitudinally of the machine. The arms 28 are pivotally mounted on a shaft 30 supported by brackets 32 at-the rear of the machine. The front portion of the perforator head 14 is supported by a crank shaft 34 journaled in suitable bearings carried by the plates 28. Cranks 36 on the ends of the shaft 34 are received in sockets at the upper ends of links 38 that are pivo-tally connected at their lower ends to fixed members as indicated at 39, Fig. 3. I

A worm gear 40 on thecrank shaft 34 meshes with a worm 42 on av shaft 44 that is journaled With the in a bearing bracket 46 carried by the pivoted frame 23. The shaft 44 is coupled to the shaft of the motor It to be driven thereby. When the motor I6 is operating, it drives the crank shaft 34 through the medium of the worm 42 and worm gear 45, causing the perforator head M to pivot downwardly to drive the punches 20 selected by the actuating rings 24 through the sheet S disposed therebelow to mark the sheet, the perforator head 14 then being restored to its upper position as the crank shaft 34 completes its cycle. 7

The motor-driven actuating mechanism for the perforator head [4 includes a cycle clutch of the character disclosed in the aforesaid Rix patent. Referring to Figs. 3, 4, 9 and 10, the clutch includes a pair of release plates or discs 48 mounted on the crank shaft 34 between a pair of the supporting plates 28 of the perforator head l4. Each release plate 48 has a notch 50 in its periphery adapted to receive the'nose of a latch or pawl 52 that is secured to a rock shaft 54 journaled in the frame plates 23 of the perforator head 14. A plurality of rollers 49 are disposed in recesses in the driven clutch ring 53 which is keyed to the crank shaft 34, the ends of the rollers 49 extending through openings 51 in the discs 48. The rollers 45 are engageable and disengageable with respect to the inner cylindrical surface of the worm gear 49, which constitutes the driving clutch member. Coil compression springs 55 seated in suitable pockets in the driven clutch ring 53 tend to urge the rollers 49 into binding relation with the driving and driven clutch members.

When the latches 52 are withdrawn from the release plates 48, in a manner which will be described presently, the coil compression springs 55 urge the clutch rollers 49 forwardly into wedging engagement with the driving and driven clutch members 49 and 53, the plates 48 also being pushed 'ahead inthis operation. The motor 16 then rotates the crank shaft 34 through the medium of the engaged clutch parts until the release plates '48 have about completed a revolution, when the latches 52 will again seat in the notches 56 thereby disengaging the clutch and stopping the crank shaft 34 in a definite position. This action occurs as a result of the'plates 48 being arrested by the latches 52 and forcing the rollers 45 into the larger portions of the recesses 5i. To prevent rebound of the driven clutch member 53 there is provided a pair of coil tension springs 59, Figs. 3 and 4, each secured at oneend to, the'upper endof an operating link 38 and at its other end, to the frame of the perforator head 14. These springs are strong enough to preventany re-engagement of the rollers 49 with thedriving clutch member so long as th plates 48are held by the latches 52.

For operating the latches 52 there is provided a solenoid 56,]Figs .'2, 3 and '7, mounted on the base. Illof the machine. The plunger of this solenoid is connected by a link 58 to a rocker arm 50 that. is secured to the rock shaft 54. When a perforating operation ,is to be effected, the solenoid 551s. momentarily energized in a manner to be explained herein after, thereby withdrawing the latch 52 fromthe notch 55 to permit engagernent ,of the cycle clutch. An arm 62 affix ed tothe shaft 54 is connected to a plate or lug-'54fwhichdepends' therefrom as shown in Figs. 2 and 3. A "restoring springjES extended between the lug 64 and ananchor on the frame 28 tends to urge the latch 52 toward the periphery oftliehotched disc 48.

A motor-controlling switch 68 is mounted on the frame 28 of the perforator head [4 in position to be actuated by a roller 10 on the arm 62. When the solenoid 56 is energized to rock the shaft 54, the arm 62 is shifted and effects closure of a pair of contacts in the switch 68. The circuit connections betweenthe switch 53 and the motor I6 will be explained more fully in a subsequent description.

The rock shaft 54 may also be operated manually by a push rod 12 which is shiftably mounted in the die shoe l2 in horizontal alignment with the lower end of the lug 64 on the rocker arm 62. The rod 12 extends through the die shoe IE to the front of the machine and terminates in a push button 14 which projects from the front edge of the die shoe l2, as shown in Figs. 1 and 3. A spring 15 is provided for restoring the push rod 12.

The sheet S which is to be perforated is inserted, in the gap between the punch holder 22 and the die plate 26. In many cases it is desirable that the perforation be registered accurately on sheet S, both with respect to the leading edge and one side edge; Thisis particularly important where the perforated information or data must be located close to the aforesaid edgeas illustrated in Fig. 6. Paper sto' pins 17, Figs. 2, 5 and 6, afiixed to the die shoe I2 are located to arrest the leading edge of the sheet sat a predetermined line of registration indicated by the dot-dash line L in Fig. .5. Toprovide for the side location of the sheet S, a side stop or gage 18, Figs. 5 and 6, is installed on the die shoe 12. This gage if necessary may be disposed within the aforesaid gap. 7

To insure accurate placement of the sheet S prior to operation of the perforator head, I have provided a pair of paper detecting switches and 82, Figs. 2, 3, 5, 6 and 7. These paper detecting switches (hereinafter referred to as paper switches) are very sensitive and are capable of being operated by relatively light forces. The switches 86 and 82 are provided'with paper detecting fingers or members 84 and 86, respectively, each pivotally mounted on the frame of its switch and normally urged into the position shown in Fig. 5 by a light torsionspring (not shown). Switches of this type are available on the market. The switch 80 is mounted on the die block l2 with the front edge of its detecting finger 84 slightly beyond side stop 18 and normally being slightly in advance of the predetermined line of registration L, Fig. 5, for the leading edge of the sheet. The switch 82 is mounted on a' portion of the perforator head 14 and has an elongated detecting finger 86 that normally is disposed in advance of the line of registrationL for the leading edge of the sheet S.

The switches and 82 are arranged to close when their detecting fingers 84 and 86 are moved by the leading edge of the sheet S substantially into coincidence" with the line L. Should the sheet S be inserted with its side edge not against the side stop 18, the leading edge could actuate detecting finger 86 and close the contact in paper switch 82. Sheet S however would miss detecting finger 84, and as paper switches 80 and 82 are" connected in series, the clutch-operating circuit through these switches would not be closed and thus no perforation wouldbe made in sheet S. This feature therefore insures that side registration will be maintained within reasonable limits.

Should more accurate side registration be required, resort may be had to a modified arrangement such as is illustrated in Fig. 8 wherein the JQQTZA paper switch 88 of Fig. 2 is located in alignment withthe side stop I8 as indicated at 88a. The detecting finger 84a of switch 88a is adapted to be engaged by a side edge portion of the sheet Shear the line of registration defined by the paper stop pins 11. This arrangement insures side registration which is accurate to within of an inch. While a left-hand location of the switch 88a and side stop 18 is illustrated, these parts obviously will function equally well on the right-hand side of the sheet S.

Referring now to the wiring diagram, Fig. '7, in conjunction with Figs. 2, 5 and 6, the two paper switches 80 and 82 are connected in a circuit which includes the solenoid 56 and a control relay 88 that may be mounted on any convenient portion of the structure such as the base I8. Preferably the switches 80 and 82 are series-conn'ected. Wires 82 and 94 serve to connect the electrical apparatus with a source of electric current. The electrical circuit is closed from the wire 92 by a master switch 88. A series circuit extends from the switch 90 through the two paper switches 88 and 82 and through normally closed contacts 83 of the relay 88 to the solenoid 56, the circuit then being completed through the winding of the solenoid 56 to the wire 94 when both of the switches 88 and 82 are closed.

.Switches 89 and 82 are closed only when the leading edge of a sheet S is accurately registered withrespect to the line L, Fig. 5. If the leadin edge is crooked, one or the other of these switches may remain open. It should be noted also that one of the lateral edges of the sheet S must be against the side stop 18 or very close thereto before the switch 80 can close. This arrangement insures accurate placement of the sheet S as a condition precedent to establishment of an electrical circuit to the solenoid 56 when the perforator is being operated automatically in response to insertion of a sheet.

Assuming that a sheet S is properly positioned in the machine to effect closure of both switches 89 and 82, the solenoid 56 is energized immediately upon insertion of the sheet S and operates to rock the shaft 54, thus effecting withdrawal of the latches 52 from the notches 59 in the release plates 48 (only one of which is illustrated in Fig. 7) and simultaneously closing I the motor switch 68. Circuit through the motorlB thereby is closed, causing the motor to startoperating concurrently with engagement of the clutch that couples the worm gear 48 to the crank shaft 34. The perforator head 14 thereupon is actuated to drive the selected punches 29 into the sheet S whereby to mark sheet S.

To manually operate the machine independently of the paper switches 80 and 82, the button 14 is pushed to actuate the rod 12. This results in rocking the shaft 54, with the effect just described.

The control relay 88 is provided for the purpose of interrupting the energizing circuit to the solenoid 56 when the notch 50 in each release plate 48 has moved out of alignment with the nose of its latch 52, so that the spring 66 may restore the latch 52 whereby the'clutch is disengaged at the end of a cycle when the notch 50 again moves into alignment with latch 52. The relay 88 also functions to prevent a repetition of the perforating operation so long as the perforated sheet S remains in position to maintain the switches 88 and 82 closed. To prevent relay 88 from interrupting the circuit to solenoid 56 before the clutching mechanism has become.

engaged, I propose to incorporate in the circuit a third switch (hereinafter referred to as a cutoff switch) 96,;Figs. 2, 3 and'l. Thissw h eliminates the necessity of using a more-expensive time'relay in placerof thenormaloperation relay 88. The circuit connection 'between cutoffswitch 86 and relay 88 ,willbe explained more fully in the subsequent description. A bracket 98, Fig. 3, supports the switch- 96 in; position to be operated by a portion of the-frame 28 ofthe perforatorhead l4 when thela-tter isactuated by themotorl6.

When the perforator head; l 4 ;i in its-upper position, the relay 88 is in; a deenergiz-ed condition, during which time its contacts 93 areclosed and the contacts 98 of thisrelay are open. When the perforator head I4 descends, some mechanism relative to this operation actuates the button I88 of cut-off switch 96. While it is preferable that this take -.pl ace'early-in the cycle, it may actually take .place'at any time until just prior to completion of the cycle of operation.

This causes switch 96 to. close and: complete: a circuit from wire 92 throughtheswitch-BO, the paper switches 89 and 82-, cut-off switch 96 and coil of relay 88 to the wire 94. Relay 88=energizes to open its contacts 93 and close'its contacts 98. Opening of contacts 98 results in deenergization of the solenoid 56. The restoring spring 66 returns the latchjZ-into engagement with the periphery of the disc-48. The motor switch 68 is so constructed,- however,.- thatit remains closed so long asthenose of the pawl 52 is riding on the periphery of the release plate.

48. Hence, motor [6 remainsenergized until the pawl 52 again enters thev notch 59 at the completion of the cycle. Thus the perforator head I4 is caused to descend and effect perforation of the sheet S and is then restored into its upper position. 7

When the relay contacts 98 are closed as just described, a holding circuit is established for the relay 88, this circuit being traced fromthe wire 92 through the switch 8.0,".ithe paper switches 88 and 82, the relay contacts98fand the coil of relay 88 to the wire 94. Opening of,.'the cutv-off switch 96, therefore, is without effect inasmuch as relay 88 is maintained energized'fthro'ugh theholdin holding circuit f-or'relay' 88 is broken and this relay then deenergizes to open its contacts 98 and close itscontacts 93. The circuit thereby is conditioned for another automatic perforating operation when a new sheet S1 is inserted in the machine.

From the foregoing description it .is apparent that I have provided a perforating machine which fulfills the abovejstated,objects of the invention. The machineoperates rapidly and accurately to perforate ajsheetfiwhereby said sheet is marked in responseito insertionof the sheet in the machine. Unwanted repeat operations are prevented by simplefand dependable means including the relay8 and cutoff switch 96. Hence, there is noIdangertl'iat-a sheet will be mutilated by a second-f egistratio-n ,means,

and 82 in conjunction with the side stop 18, insures accurate iqcanon of the perforations in the sheet S and is particularly advantageous where theper'foi'ated data islocated very close to the edgeof the sheet, as indicated'in Fig. 6. The fixedstops 11, 18 define limit reference lines for side and end edges of an inserted sheet and the detecting members are engageable with spaced portions of the sheet when its edges substantially coincide with the reference lines. The corner of such reference lines is defined substantially by either of the switch arms 84', 84a and theseswitch arms are curved along" their respective reference lines and each is convex toward the other reference line so that either one of the detecting'members is movable to actuate its switch in response to positioning of a sheet with itsedge's Substantially coinciding with the aforesaid reference lines. I

It is obw'ous that various changes maybe made in' the specific embodiments set forth for purposes of illustration without departing from the principles of the invention. The invention is accordingly] not to be limited to the precise details disclosed herein but includes all modifications thereof within the spirit and scope of the appended claims.

The invention is hereby claimed as follows:

1. In a perforating machine having a movable perforator head'and cyclically operable actuating means for said head, the combination comprising switch means, operation-effecting means responsive to closure of said switch means for initiating operation of said actuating means, a circuit cuton' device arranged to'be operated in response to movement of the perforator head, disabling means responsive to operation of saidcut-ofi? device for terminating the operation of said actuating means at the'end of a cycle, and circuit holding means controlled by said switch means to maintain said disabling means effective so long as said switch means remains closed, whereby the perforator head is actuated only once for each closure of said switch means.

"2..In a perforating machine, switch means, a movable perforator head, driving means, means including'a clutch for coupling said'perforator head to. said drivingmeans, clutch-operating means responsive to closure of said switch means for effecting engagement of said clutch, .declutch ing means effective when operated to disengage said clutch, a circuit cut-01f device responsive to operation of said perforator head forefiecting operation of said declutching means, and holding means responsive to operation of said cut-01f device for jmaintaining said declutching means operative. I v Q 3. In a perforating machine, sheet-detecting switch means, a'mov'able perforator head, driving means, means includinga clutch for coupling said perforator head to said driving means, clutch-operating means effective when actuated to engage said clu't'ch and eiiective when'released to disengage said clutch, said clutch-operating means being actuated by closure ofsaid sheet-.

detecting switch means, a'cut-oii switch arranged to be closed in response to a'ctuation'of said perforator head, a control relay arrangedto be operated by closure of said cut-off switch for releas ing said clutch-operating. means, and a holding circuit for said relay to prevent repetitive action. of :said clutch-operating means -s'oglon g as said switchmeans remains closed;

'14. In afperforatingmachine, detectingimeans for sensing the presence of a'sheet to be perforated in the machine, a movable perforator head, drivingm'eans, means including a clutch to couple said perforator' head to said driving means, a circuit cut-off device arranged to be operated in response to actuation of said perforator head, and operation-limiting means controlled jointly by said cut-off device and said detecting means to effect disengagement of said clutch upon completion of a perforating operation and so long as the perforated sheet remains in position to be sensed by said detecting means. 3

5. In a perforating machine, a plurality of series-connected switches each having detecting means to sense the presence of a sheet to be perforated in the machine, a movable perforator head, driving means, means including a clutch to couple said perforator head to said driving means, clutch-operating means including a solenoid effective when energized to engage said clutch and effective when deenergized to disengage said clutch, a relay normally effective to condition a circuit for energizing said solenoid, said circuit being completed by closure of all said switches, and a cutoff switch arranged to be operated by said perforator head upon actuation thereof to operate said relay for interrupting the energizing circuit to said solenoid.

6. In a perforating machine, a plurality of series-connected switches each having detecting means to sense the presence of a sheet to be perforated in the machine, a movable perforator head, driving means, means including a clutch to couple said perforator head to said driving means,

clutch-operating means including a solenoid ef-' fective when energized to engage said clutch and effective when deenergized' to disengage said clutch, circuit means electrically connecting said solenoid to said switches for energizing said solenoid when all said series-connected switches are closed, a cut-off switch arranged to be operated by said perforator head upon actuation thereof, a disabling relay responsive to operation 01" said cut-off switch for interrupting the electrical connection between said solenoid and said series-comiected switches, and holding circuit means including said series-connected switches for maintaining said relay effective to interrupt said electrical connection so long as the perforated sheet remains in position to be detected by said switches.

'7. In a perforating machine, a plurality of series-connected switches each having detecting means to sense the presence of a sheet to be per forated in the machine, a. movable perforator head, driving means, means including a clutch to couple said perforator head to said driving means, clutch-operating means including a solenoid effective when energized to engage said clutch and effective when deenergiz'ed to disengage said clutch, a relay having an operating coil and ineluding first contacts closed only when said relay trically connecting said cut-oil" switch in abircuit with the operating coil of said relay, and

still other circuit-means electrically connectingv said detecting switches and said, relay coil in a series circuit closable thronghsaid second relay 1 contacts.

8. In a perforating machine, a movable perforator head, actuating means for said perforator head, sheet registering means including a side stop to engage a side edge of a sheet inserted in the machine and a pair of detecting members respectively disposed to sense portions of the leading edge and said side edge of the sheet, the latter one of said members being disposed in proximity to a corner of aproperly registered sheet and spaced from the other detecting member in substantial alignment with said side stop, switches respectively arranged to be closed by said detecting members in response to the sensing of portions of the sheet thereby, and electrical operation-effecting means responding only to closure marking head and cyclically operable actuating of all said switches for operating said actuating means.

9. In a perforating machine, a movable perforator head, actuating means for said perforator head, sheet registering means including a side stop to engage a side edge of a sheet inserted in the machine and a pair of yieldable sheet-detecting members respectively engageable with portions of the leading edge and said side edge of the sheet, the latter one of said detecting members being disposed in proximity to a corner of a properly registered sheet and spaced from the other detecting member in substantial alignment with said side stop, switches respectively arranged to be closed by actuation of said detecting members, and electrical operation-effecting means responsive only to closure of all said switches for operating said actuating means.

10. In a perforating machine, a movable perforator head, driving means, means including a clutch to couple said perforator head to said driving means, clutch-operating means including a solenoid effective when energized to engage said clutch and effective when deenergized to disengage said clutch, a pair of detecting switches each having a yieldable sensing member adapted for engagement with an edge of a sheet inserted in the machine, a relay having an operating coil and including first contacts closed only when said relay is not operating and second contacts closed only during operation of said relay, a cut-off switch arranged to be closed in response to actuation of said perforator head, circuit means electrically connecting said solenoid and said detecting switches in a series circuit closable through said first relay contacts,rother circuit means electrically connecting said cut-off switch in a circuit with the operating coil of said relay, and still other circuit means electrically connecting said detecting switches and said relay coil in a series circuit closable through said second relay contacts.

11. In combination with an apparatus as set forth in claim 10, a side stop for registration of the sheet in the machine, one of said yieldable sensing members being disposed substantially in alignment with said side stop, and both said sensing members being effective to close their respective detecting switches when the sheet is properly registered.

12. Ina marking machine having a movable means for said head, the combination comprising switch means, operation effecting means responsive to closure of said switch means for initiating operation of said actuating means, a cut-off device arranged to be operated in response to movement of the marking head, disabling means responsive to operation of said cut-off device for terminating the operation of said actuating means at the end of a cycle, and holding means controlled by said switch means to maintain said disabling means effective so long as said switch means remains closed, whereby the marking head is actuated only once for each closure of said switch means.

13. In a marking machine, switch means, a movable marking head, driving means, means including a clutch for coupling said marking head to said driving means, clutch operating means responsive to closure of said switch means for effecting engagement of said clutch, declutching means efiective when operated to disengage said clutch, a cut-off device responsive to operation of said marking head for effecting operation of said declutching means, and holding means responsive to operation of said cut-off device for maintaining said declutching means operative.

14. In a perforating machine, a movable perforator head, actuating means for said perforator head, sheet registering means including fixed stops defining limit reference lines for side and end edges of a sheet inserted in the machine and a pair of yieldable sheet detecting members respectively engageable with spaced portions of the sheet when edges thereof substantially coincide with said reference lines, switches respectively arranged to be closed by said detecting members in response to the sensing of portions of the sheet thereby, an electrical operation-effecting means responsive only to closure of both of said switches for operating said actuating means, one of said detecting members being disposed adjacent the corner formed by said reference lines and including a switch arm curved in a direction along one reference line and convex toward said other reference line and movable to actuate its switch only in response to positioning of a sheet with edges substantially coinciding with said reference lines.

JOHN R. ANDERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,197,788 Birscher Sept. 12, 1916 1,288,402 Gale Dec. 17, 1918 2,427,418 Rast Sept. 16, 1947 FOREIGN PATENTS Number Country Date 404,066 Great Britain Jan. 11, 1934 525,862 Germany May 29, 1931 

